The broad objectives of this research are to enhance the basic knowledge of the brain processes involved in generation of event-related slow potentials and to provide information regarding the mechanisms of alteration of these potentials in psychiatric disorders and by pharmacological agents. A rat model will be developed and characterized as a model for the study of brain slow potential responses. Classical and operant conditioning procedures will be used to generate behavior-related cortical slow potential responses. The responses obtained from the rat will be compared with those which have been recorded from other species and from man (i.e., the contingent negative variation or CNV). The relationship between the level of CNS arousal and the magnitude of slow potential responses will be studied by examining the influence of drugs which alter arousal on the slow potential responses.